Gouda Mohamed Zakaria, Roberge Steeve, Khiari Lotfi, Benjannet Rim, Desrosiers Mélanie
Department of Soil Science and Agrifood Engineering, Laval University, Quebec, QC, G1V 0A6, Canada; Centre d'Expertise en Analyse Environnementale du Québec, Ministère de l'Environnement, de la Lutte Contre les Changements Climatiques, de la Faune et des Parcs, Québec, QC, G1P 3W8, Canada.
Centre d'Expertise en Analyse Environnementale du Québec, Ministère de l'Environnement, de la Lutte Contre les Changements Climatiques, de la Faune et des Parcs, Québec, QC, G1P 3W8, Canada.
Chemosphere. 2025 May;377:144357. doi: 10.1016/j.chemosphere.2025.144357. Epub 2025 Mar 28.
Organic fertilizing residuals (OFRs) enhance soil fertility and support sustainable agriculture due to their rich nutrient and organic matter content. However, these materials are increasingly recognized as a significant source of microplastics (MPs) in agricultural soils, raising concerns about the safety of agroecosystems. Therefore, there is an urgent need to develop a reliable workflow for MP analysis in diverse OFRs, given the challenges of extracting small MPs from such organic matter-rich matrices. This study presents an oxidative-alkaline tandem digestion method that achieves an average organic matter (OM) removal efficiency of 93 % across various OFRs. In addition, density centrifugation with NaCl and ZnCl brines was utilized to recover six microplastic polymers (PP, PVC, PET, PS, PE, and HDPE), achieving a recovery rate of over 95 % for large MPs (600 μm-4.75 mm) and over 83 % for small MP-PE beads (38-45 μm). Micro-Fourier transform infrared spectroscopy (μ-FTIR) analysis confirmed that digestion and separation steps did not affect MPs' spectral integrity and chemical identification. To validate the workflow, we applied it to analyze MPs in various OFRs from Québec, allowing for the successful detection of 19 MP polymers with sizes down to 10-50 μm. This workflow can be applied to multiple OFRs to extract, quantify, and characterize MPs. Ultimately, this workflow will facilitate efficient MPs analysis across diverse OFRs, providing essential data for robust risk assessment and better environmental management to mitigate MP pollution from OFR applications in agricultural soils.
有机肥料残渣（OFRs）因其丰富的养分和有机质含量而提高土壤肥力并支持可持续农业。然而，这些物质越来越被认为是农业土壤中微塑料（MPs）的重要来源，引发了对农业生态系统安全性的担忧。因此，鉴于从这种富含有机质的基质中提取小尺寸微塑料存在挑战，迫切需要开发一种可靠的流程来分析不同OFRs中的微塑料。本研究提出了一种氧化-碱性串联消化方法，该方法在各种OFRs中实现了平均93%的有机质（OM）去除效率。此外，利用NaCl和ZnCl盐水进行密度离心，以回收六种微塑料聚合物（PP、PVC、PET、PS、PE和HDPE），对于大尺寸微塑料（600μm - 4.75mm）回收率超过95%，对于小尺寸微塑料PE珠（38 - 45μm）回收率超过83%。微傅里叶变换红外光谱（μ-FTIR）分析证实，消化和分离步骤不会影响微塑料的光谱完整性和化学鉴定。为了验证该流程，我们将其应用于分析魁北克各种OFRs中的微塑料，成功检测到尺寸低至10 - 50μm的19种微塑料聚合物。该流程可应用于多种OFRs，以提取、量化和表征微塑料。最终，该流程将有助于高效分析各种OFRs中的微塑料，为进行有力的风险评估和更好的环境管理提供关键数据，以减轻农业土壤中OFRs应用产生的微塑料污染。
